The present invention relates to a gate valve having special internal sleeve arrangements for sealing in all operative positions of the gate. The valve of the invention is particularly adapted for the control of abrasive slurries and the like, but may be used for any fluid control. The invention is effectively an improvement over the type of valve disclosed in Clarkson U.S. Pat. No. 4,257,447 issued Mar. 24, 1981, differing thereover mainly in the internal sleeve arrangement with its enclosed stiffening element.
The above-identified Clarkson patent discloses a gate valve wherein a reinforcing ring is mounted at the outer periphery of an internal sleeve, with an axially extending annular lip on the end of the sleeve at the gate, and with similarly constructed sleeves at both sides of the gate in a valve assembly.
Previous valve configurations in which at least one sleeve or seal member having an enclosed ring is employed with a valve closure member are described in the following U.S. Pat. Nos.: 2,873,943 to Williams; 3,659,822 to Nagy; 4,201,365 to Paptzun et al.; 4,603,864 to Raftis; 4,623,122 to Gambetta; and 4,625,942 to Nelson.
The present invention distinguishes over the aboveidentified Clarkson patent and the other patents mentioned above by providing a special sleeve structure at opposite sides of the gate having a novel arrangement of a stiffening element enclosed within each sleeve.
It is therefore a major object of the invention to provide a novel valve assembly wherein resilient sleeve units at opposite sides of the gate have a special configuration of a stiffening unit enclosed within each sleeve.
A further object of the invention is to provide a novel gate valve assembly wherein the inner ends of axially compressed sleeve units engage opposite sides of the gate in the valve closed condition and sealingly engage each other in the valve open condition, and are of special structure providing improved coaction between the sleeve units and the relatively slidable gate.
Another object of the invention is to provide a novel gate valve assembly wherein each sleeve end adjacent the gate has an encircling thin reinforcing band of metal or the like that is enclosed within the sleeve in proximity to a radially extending gate engaging and guiding surface.
A further object of the invention is to provide as a removable and replaceable subassembly for a gate valve a novel sleeve unit that includes a resilient cylindrical sleeve body having at the end adjacent to the gate an axially extending annular compressible sealing lip and a stiffening strip or band of metal or the like in proximity to that end and completely enclosed within the sleeve body. Pursuant to this object the lip may be an annular rounded end formation projecting axially from the sleeve end at the inner periphery, and the guide surface may be provided by enclosing within the outer periphery of the sleeve at that end an annular strip of thin metal or similar material. Also the opposite end of the sleeve body may be formed with an integral radial flange adapted to be compressed between the valve housing and the pipeline when installed.
Further objects of the invention will appear as the description proceeds in association with the appended claims and the accompanying drawings.